A method for performing mobility by a user equipment (UE) in a wireless communication system is provided. The method includes: receiving Physical layer Cell Identity (PCI) split information from a network, the PCI split information indicating a predetermined set of at least one PCI reserved for a predetermined cell type; receiving system information from at least one candidate cell, the system information comprising a PCI for each cell; measuring the at least one candidate cell; determining whether to apply the PCI split information for selecting a target cell; selecting the target cell; and performing the mobility to the target cell. If it is determined that the PCI split information is applied, the step of selecting the target cell includes: excluding at least one cell has a PCI included in the predetermined set; and selecting the target cell among at least one remaining cell.